Electrical switch apparatus for operating devices on aircraft, and other purposes



March 26, 1946. H TREVASKB y 2,397,386 A ELECTRICAL SWITCH APPARATUS FOR March 26, 1946. H. TREvAsKls 2,397,386

ELECTRICAL SWITCH APPARATUS FOR 4 OPERATING' DEVICES 0N AIRCRAFT, AND OTHER PURPOSES Filed Oct. 9, 1945 2 Sheets-Sheet 2 Patented Mar. 26, 1946 ELECTRICAL SWITCH APPARATUS FOR P- ERATING DEVICES ON AIRCRAFT, AND OTHER PURPOSES Henry Trevaskis, Solihull, England, assignor to Dunlop Rubber Company' Limited, London, England, a British company v Application- .October 9, 1943, SerialNo. 505,702

In Great Britain August29, 1942y s claims. (o1. 20o-+157) My invention relates to electrical switch apparatusr for effecting collective or selective actuation of a plurality of electrical circuits or devices, and `particularly relates to apparatus for controlling the operation of automatic guns on aircraft rin conjunction with a cine camera. The

invention has for its object to enable such' camera to be operated independently of such guns and to ensure that the camera is operated automati- Y cally with the guns when any or all of the guns erate said gun operating switches either severally or collectively, or may be operated by selected local pressure independently of said gun operated switches. My invention also comprises a safety plate movable to a position to expose the pressure areas controlling the gun operating switches or to a position to cover these areas and expose only the selective camera operating switch area .of the pressure plate and at the same time to open a safety switch which renders -the circuits of the gun switches inoperative. It will be understood that these switches may be of any suitable type and that the safety switch may be operated by the safety plate through any suitable mechanism.

In order that the said invention may be easily `understood and readily carried into effect, the same will now be Vdescribed with reference to the accompanying drawings in which:

Fig. 1 is a sectional View of the apparatus on the line A--A of Fig. 2; y

Fig. 2 is a plan view of the apparatus shown in Fig. 1;

Fig. 3 is a plan View of the apparatus with the pressure plate and flap removed; and

Fig. 4 is a part sectional View on the line B-B v of Fig. 3.

the base of the trough as shown in Figs. 1 and 4, Thebody portion 2 is shaped to pass a multiple cable through its free end which is threaded to engage a cap 3, Fig. l, by which the body portion is clamped to a flying control handle 4, Fig. l.

' Thetrough is closed by a pressure plate `5, Figs.

1, 2 and 4 which conceals the switch mechanism and which is mounted in the trough so that the pressure plate can be bodily or angularly displaced by thumb pressure applied to it at one of four areas 5a, 5b, 5c, 5d, Fig. 2, such angular displacement serving to operate one or more electrical switches housed in the trough.

In addition to the pressure plate 5 manually operable means are provided in the form of a flap 6, Figs. 1 and 2, which is hinged to the housing to extend substantially across the centre of the pressure plate so as to fold down upon a portion of the plate and thus to act as a safety device which prevents thumb pressure being applied thereto at 5a, 5b, or 5c which control the vgun switches that is to three of the four areas in the safe position of the ap, While permitting the application of such pressure to the fourth remaining area 5d which may operate the camera switch. The flap 6 is shown in a mid-open position in Fig. 2, but in the firing position of the iiap shown by dotted lines in Fig. 2 the three pressure plate areas 5a, 5b, 5c are exposed to permit thumb or linger pressure to be applied to two of these areas independently as at 5a or 5b whereby selective actuation may be effected of two gun operating switches l and 8, Fig. 3, or to a third area 5c whereby collective actuation of the same two switchesis effected. The switches 1 and 8 each controls the Afiring of a particular gun or group of guns, whereas pressure applied to the third area 5c serves to operate both these switches and the guns connected thereto simultaneously.

The fourth area 5d 'of the pressure plate which is exposed when the hinged iiap B is in the safe position controls the operation of a third operating switch mechanism I3--I3e of a cine camera control circuit. This mechanism includes a bowed spring id and a plate i3, preferably of insulating material, supported thereon and depressed by pressure on the area 5d. Although the flap when moved to the ring position covers the fourth aread of the pressure plate 5 and only exposes the areas 5a, 5b, 5c, pressure applied to any of these three exposed areas also displaces the plate i3 to deflect and close Ythe camera switch so thatthe camera is always automatically operated in conjunction with any or all of the guns.

Movement of the hinged flap 6 from the safe position covering the multi-area side of the pressure plate to the ring position shown in dotted lines in".'Fig.=2 also effects actuationof a' master switch for `connecting'or disconnecting' the supply of electric current to both the gun operating switches 'I and 8 independently of movementfcf the pressure plate. Whenthe-flap is inthe safe position the master switch is opened. and Ywhenthe flap is in the firing position the master switch is closed.

The master switch, Fig. 3,- comprisesza'hook shaped spring loaded member 9 having a contact 9a at the end of its shank and is pivotally held at the bight of the hookA by a peg II'which.has a rotatable stem I Ia in the bight of themeznber 9. The peg II and the stem IIa are mountedin a corner of the trough I so that the member 9 may i Aswing-the contact Batoward or from a stationary contactb to make and break a circuit tobotli of the gun operating circuits. AThe stem or spindle IIal has a sidewise tongue IIb radial tothe axis of rotation of'thespindle I Iav and notched at i yits free end to receive the free end of a spring IIc, the other end of which is secured to the .member 9 near the contactlSa. Thespindle `I la is also provided with a knife edge I Iolwhich bears `against the bight` of the member 9. The result `is that when the spindle Ila is rotated inone `direction it causes .the contactV Sciuto snap away from the contact 9b to'breakf the 'circuit and .when turned-in the'opposite direction causes the contact .9a to snap into contact with the terminal 1:91? the spring passingV through the;dead center :between these two movements.

The spindle IIa is rotated by the hinged flap 6 being rotated to the position shown in Fig.' 3 to cause a quick break of the circuit when the flap is moved to safety position to coverthe areas ..15a, b, and c, andbeing.:movedlin the. opposite direction when theflap is moved to thebroken lineposition, Fig. 2. For thispurposethe nap 6 `isv rotatably lsupported by ,trunnions Ga `and* 6b, the trunnion Ga'being mounted in a pin 6c and thetrunnion 6b` in thepin II and having a suit- .able `transmission to thespindle IIb. :Any suitable connection may be used andthe detailsI are omitted from the drawings for the sake of clearness.

The gun operating switches 'I and 8 coact with the switch plate I3 which is positioned parallel .to the bottom of the trough and carried on a perpendicular hollow plunger I6 sliding in a flanged sleeve I5. The switch` plate I3 isdisplaceable bodily downwardly towards the base of the trough against the load of the bowed spring' 'I3d carried by the under surface ofthe switchy plate LIS to cause the spring to beflexed upwardly so`that a camera circuit contact I3e, Fig. 1, at the centre of the bowed spring makes a quickupward movement into electrical contact with the overhanging portion of thexed contact 9b referred to above.

The switch plate I3 has two projecting'limbs I 3a, ISb which lie beneath and 'are spaced from two ball contacts 'Ill formed Yon theupstanding ends of the gun switches 'I and 8 which yieldingly support the pressure plateN B'under -the load of springs I,'Fig. 4; each of these switches 'I a-nd 3 formsV part of an electrical circuit to a single gun or group of guns. VThe switch plate- I3 also has a `projection I3c at the side opposite to saidlimbs and co-acting with a stud orprojection not shown `on the under side of thefourthareadnf the -nect two separate circuits through the lead wire `ll-and the contact 9a with the return contact #9b. This contact 9b may be connected in the circuitfthrough anysuitable connection as, for example, through the binding post 9c, Fig. 4. The

plate .I3 is not concerned in the operation of either of the switches I4 but is merely so positioned that it will be depressed when either of theseswitches I4 is depressed and it will, therefore,'cause a bowing of the spring I3cl. The

spring I3d connects the Contact I3 with a circuit through the camera so that when this contact is bowed upwardly to meet the contact plate 9b a circuit will pass through the `camera and thence return through the plate orcontactzb Aandthebinding-post 9c. yIt willbe apparent, itherefore, that the plate 9b acts as a'common returncontact for each of the gun circuits connected with it through the contact 9a and also for the cameracircuit when the latter is connected to the plate 9b through the contact I3 and the bowed :spring 15d. There will, therefore, be

'one return circuit in contact with the contact plate 9b and three separate branch circuits, one for each of the two guns and one for the camera.

The operation of the apparatus for controlling automatic guns and a camera on aircraft is as Vfollows: 'When it is desired to voperate the'camera 'without the guns theflap 6 is thrown over to the safety position to cover the pressure areas 5a, 5b,

"5c shown on the right hand side oi the pressure plate 5. The vmaster switch 9 is opened by this movement of the flap to render the gun operating switches 'I and 8 dead andthe left hand portion .5d of the pressure plate 5 is exposed for the applcation of finger or thumb pressure, whereby the pressure `plate may be moved to complete only the camera circuit normally interrupted by the-bowedspring I3d carried on the switch plate member I3.

On throwing the flap over to the ring position on the left hand side the master switch 9 is closed, thus rendering the gun operatingswitches 'I and 8 alive, and exposing only that multiarea portion of the pressure'plate which may be Vdepressed by local pressure so as selectively or 4collectively to operate one or both of the gun switches. AtV the same time the camera switch is automatically closed to operate the camera by the deflection of the bowed spring I3d to complete the camera circuit.

Having described my invention what I yclaim is: 1. -Electrical `switch apparatus in the form of a unit comprising a housing having a plurality of `operating switches, a masterswitch, a pressure .is movable between 'two positions in each of Awhich a portion of the. surfacerof `said plate :is covered vby, the iiap.

3.: Electrical -switch apparatus comprisingla fpressure plate, al pairof spring loaded switch members contacting the undersurface of said pressure plate and displaceable singly or together by surface pressure on the plate, a single switch member plate normally spaced from the free ends of said switch member and a supporting plunger positioned in sliding contact within a portion of the housing, said switch members making elec trica-l contact with said plate when depressed.

4. Electrical switch apparatus comprising a housing, three operating switches spaced in said housing, a pressure plate movable to operate said switches, two of said switches having operating elements positioned below spaced areas of said pressure plate to permit said switches to be operated independently by selective depression of said areas and the remaining switch being positioned to be operated by a depression of said plate intermediate said spaced areas and means comprising a hinged nap to cover or uncover said spaced areas of said pressure plate.

5. Electrical switch apparatus which comprises a housing having a pair of switches, said switches being spaced apart, a pressure plate having spaced pressure areas above said switches to opcrate said switches severally by Selected depression of said areas, a master-switch controlling both said switches, an independent switch in said housing, said independent switch being positioned between said spaced areas to be operated by depression of either of said areas and means comprising a hinged ap to cover the spaced areas of said pressure plate and to open said master switch when in one position and to uncover said spaced areas and close said master switch when in an alternative position.

6. Electrical switch apparatus comprising a house, a pressure plate in said housing, a pair of spring loaded switch members contacting the undersurface of said pressure plate at separated areas and displaceable singly by pressure on a selected one of said areas or together by surface pressure between said areas, a single switch member plate beneath and normally spaced from the free ends of said switch members, a supporting plunger for said switch member plate in sliding contact within a portion of the housing, said switch members making electrical Contact with said switch member plate when depressed, a spring member supporting said switch member plate and a third switch actuated by said switch member upon depression of said switch member plate.

'7. The switch of claim 6 in which said spring member is a bowed spring and said third switch is carried by said spring to come into contact with said switch member plate when the latter is depressed.

8. The switch of claim 6 in which said pressure plate contacts said switch member plate at an area out of alignment with said spring loaded switch members.

HENRY TREVASKIS. 

